The present invention provides a chromatographic separation process for recovering a polyunsaturated fatty acid (PUFA) product from a feed mixture, which comprises: • (a) purifying the feed mixture in a first chromatographic separation step using as eluent a mixture of water and a first organic solvent, to obtain an intermediate product； and • (b) purifying the intermediate product in a second chromatographic separation step using as eluent a mixture of water and a second organic solvent, to obtain the PUFA product, wherein the second organic solvent is different from the first organic solvent and has a polarity index which differs from the polarity index of the first organic solvent by between 0.1 and 2.0, wherein the PUFA product is other than alpha-linolenic acid (ALA), gamma-linolenic acid (GLA), linoleic acid, an ALA mono- di- or triglyceride, a GLA mono- di- or triglyceride, a linoleic acid mono, di- or triglyceride, an ALA C
